关于JSP/Servlet文件上传与下载

最近Java项目上有个文件上传的功能需求，当然有上传就存在对应的下载需求。由于项目的框架由前辈搭建好了，对于功能上的需求就直接往框架中添加模块，完全采用CTRL+C/V的方式在已有的代码上做相应的修改，没撒技术含量，就这个小的功能需求对于目前这种景况也算是一个插曲 – 需要自己实现。

通过多天的代码编写与测试，终于完成对上传/下载的实现，先将其过程详细记录，以备后续总结。
工具：JBuilder 2006
WEB环境：tomcat 5.5(可以是JBuilder2006自带，亦可以是单独的tomcat软件)
实现方式：主要采用Servlet方式完成。

首先，实现Servlet代码如下：
上传代码：

package com.vspeed.servlet.util;

import javax.servlet.http.*;
import java.io.*;

public class ToolUpload extends HttpServlet {
    public ToolUpload() {
        super();
    }

//该方法完成对一个或一个以上文件的上传,无大小,格式限制
    public void doGet(HttpServletRequest request, HttpServletResponse response) {
        response.setCharacterEncoding("GBK");
        try {
            javax.servlet.ServletInputStream input = request.getInputStream();
            String direct = getServletContext().getRealPath("\\") + "files", //设置服务器附件保存文件夹
            //path = request.getRequestURI();//该方法在1.2以后就不建议使用
            path = path.substring(0, path.indexOf("/servlet"));
            java.io.File file = new java.io.File(direct);
            if (!file.exists()) file.mkdir(); //不存在文件夹则创建
            long fileName = System.currentTimeMillis();//获取系统时间，保证文件名的唯一性
            DataOutputStream pw = null;
            byte[] content = new byte[request.getContentLength()];
            int length = input.readLine(content, 0, content.length), loop = 1; //获取第一行信息
            java.util.Map map = new java.util.HashMap();
            String head = new String(content, 0, length - 1).replaceAll("-", "").replaceAll("\r", ""); //第一行字符串
            String tmpFileName = "", strExtentType = "";
            while ((length = input.readLine(content, 0, content.length)) != -1) { //获取上传文件名
                tmpFileName = new String(content, 0, length - 1);
                tmpFileName = tmpFileName.substring(tmpFileName.lastIndexOf("\\") + 1);
                strExtentType = tmpFileName.substring(tmpFileName.lastIndexOf("."));
                if (!map.containsKey(fileName + "-" + String.format("%03d", loop)))
                    map.put(fileName + "-" + String.format("%03d", loop), tmpFileName.replaceAll("\"", ""));
                input.readLine(content, 0, content.length);
                input.readLine(content, 0, content.length);
                tmpFileName = direct + "\\" + fileName + "-" + String.format("%03d", loop) + strExtentType.replaceAll("\"\r", "");
                pw = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(tmpFileName)));
                while ((length = input.readLine(content, 0, content.length)) != -1) {
                    if ((new String(content, 0, length - 1)).indexOf(head) > 0) break;
                    pw.write(content, 0, length);
                }
                pw.close();
                pw = null;
                loop++;
            }
            if (pw != null) pw.close();
            response.getWriter().println("Test For Upload File(s)");
            response.getWriter().println("");
            String label = "文件上传成功!\\n完成" + map.size() + "个文件的上传";
            if (map.size() == 0) label = "文件上传失败！";
            if (map.size() > 0) {
                response.getWriter().println("" + "上传文件信息" +                          "序号上传后的文件名" +  
    
    
    
                            "上传文件名");                  for (loop = 0; loop < map.keySet().toArray().length; loop++) {                      response.getWriter().println("" + (loop + 1) + "");  
    
    
    
                        String key = (String) map.keySet().toArray()[loop], name = map.get(key);  
    
    
    
                        response.getWriter().println("");                      response.getWriter().println("");                      response.getWriter().println("");                  }                  response.getWriter().println("
    
    
    
    
    
    
    
    
    
    
    
    " + key + "
    
    
    
    "." + name.substring(name.lastIndexOf(".") + 1) + "' >" + name + "
    
    
    
    
    
    
    
    
    
    
    
    ");
            }
            response.getWriter().println("alert('"</span><span> + label + </span><span class="string">"');");
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) {
        doGet(request, response);
    }

    public void process(HttpServletRequest request,
                        HttpServletResponse response) {
        doGet(request, response);
    }
}

下载：

package com.vspeed.servlet.util;

import javax.servlet.http.*;
import java.net.URLEncoder;

public class ToolDownLoad extends HttpServlet {
    public ToolDownLoad(){super();}
   //完成下载功能
   public void doGet(HttpServletRequest request, HttpServletResponse response){
    response.setCharacterEncoding("GBK");
    try{
        String strFile = request.getParameter("FileName");
        String path = getServletContext().getRealPath("\\") + "files";
        java.io.File file = new java.io.File(path + "\\" + strFile);
        if(!file.exists()){response.getWriter().println("alert('附件信息不存在！'); ");return;}
        response.setContentType("application/x-msdownload"); //设置格式
        response.setHeader("Content-Dispostion", "attchment;filename=" + strFile + "");
        java.io.FileInputStream input = new java.io.FileInputStream(file);
        int length = input.available();
        byte[] content = new byte[length];
        input.read(content);
        javax.servlet.ServletOutputStream out = response.getOutputStream();
        out.write(content);
        input.close();
        out.close();
    }catch(Exception ex){ex.printStackTrace();}
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response){
        doGet(request, response);
    }
    public void process(HttpServletRequest request, HttpServletResponse response){
        doPost(request, response);
    }
}

其次、配置Servlet，代码如下：

<servlet>

    <servlet-name>UtilUploadservlet-name>
    <servlet-class>com.vspeed.servlet.util.ToolUploadservlet-class>
  servlet>
  <servlet-mapping>
    <servlet-name>UtilUploadservlet-name>
    <url-pattern>/servlet/uploadurl-pattern>
  servlet-mapping>

<servlet>
    <servlet-name>ToolDownLoadservlet-name>
    <servlet-class>com.vspeed.servlet.util.ToolDownLoadservlet-class>
  servlet>
  <servlet-mapping>
    <servlet-name>ToolDownLoadservlet-name>
    <url-pattern>/servlet/downloadurl-pattern>
  servlet-mapping>

最后、页面代码，这里我主要采用javascript代码动态添加上传附件组件，代码如下：

<%@ page contentType="text/html; charset=GBK" %>
<html>
<head>
<title>
Test4Upload
title>
<script type="text/javascript">
var fileName = <%=System.nanoTime() %>;
   function addItem(){
    var item = document.createElement('INPUT');
    item.type = 'file';
    var items = cpanel.rows.length;
    item.name = fileName + '-'+items ; //注意这里一定要设置组件的name属性，form文件上传只认name属性，理论上讲id也应该可以的,希望有朋友能帮忙解释哈，先谢~~~~~~
    item.id = 'file' + items;
    var tr = cpanel.insertRow();
    var cell = document.createElement('TD');
    cell.align = 'right';
    cell.innerText = '附件' + items + ':';
    tr.appendChild(cell);
    cell = document.createElement('TD');
    cell.appendChild(item);
    tr.appendChild(cell);
   }
  script>
head>
<body bgcolor="#ffffff">
<center>
<h2>
JBuilder Generated JSP -- Test For Upload File(s)
h2>
    <h3>测试时间：<%=new java.util.Date() %>h3>
<hr />
<form method="post" action="/util/servlet/upload" enctype="multipart/form-data"> 
<table id=cpanel>
    <tr style='display:none'><td> td><td> td>
    tr>
    table>
    <button id='btnAdd' onclick=addItem()>添加(T)button>
    <input type=submit value=submit />
    form>
center>
<div id="divDetail">div>
body>
html>

效果图如下:

 

                                                       文件上传界面

 

 

                                                       上传完成界面

注意，最后一列提供查看下载功能。

 

 

                                                         直接点击查看界面

 

                                                        右键另存为界面